Transcript Gymnosperms
Seed-bearing Plants fall into two major categories Angiosperms Gymnosperms Seed-bearing Vascular Plants fall into two major categories • Gymnosperms – seeds naked on surface of cone scale • Angiosperms – seeds enclosed in a ripened ovary and flowers are produced GYMNOSPERM CHARACTERISTICS • From Greek words gymnos (naked) and sperma (seed) • Both Male and Female cones Land Plants Bryophytes Pteridophytes Angiosperms Gymnosperms Pteridophyte Bryophytes Seed-bearing plants also produce pollen Five Living Seed Plant Phyla • Cycadophyta • Ginkgophyta Gymnosperms • Pinophyta or Coniferophyta • Gnetophyta Angiosperms • Anthophyta Living Gymnosperm Phyla Conifers Pinophyta or Coniferophyta Cycadophyta Cycads Ginkgophyta Ginkgos Gnetophyta Gnetophytes Conifers – the most conspicuous and common gymnosperms Conifers About 70 genera with about 630 species Conifers • Conifers are well represented in the fossil record Sequoia affinis Conifers are of great ecological importance • Conifers are the dominant members of the vast Boreal forests (Taiga) Conifers are of great ecological importance • Conifers are very important members of many types of ecosystems Conifers are of great economic importance • Edible Seeds • Crates, Boxes, Matchsticks, Furniture • Telephone Poles • Turpentine and Rosin (Resin) • Fuel (Pitch) • Pulpwood • Ornamentals • Pharmaceuticals (Taxol) There are Seven Living Families of Conifers Pinaceae - Pine family Araucariaceae - Araucaria family Podocarpaceae - Yellow-wood family Sciadopityaceae - Umbrella-pine family Cupressaceae - Cypress family Cephalotaxaceae - Plum-yew family Taxaceae - Yew family Five of the Most Familiar Groups of Conifers Norfolk Island Pines Pines, Firs, Spruces Sequoias and Redwoods Junipers and Cedars Yews The Largest, Tallest, and the Oldest Plants are Conifers. All found in California • Giant Sequoias of the California Sierras are the largest • Coastal Redwoods are the tallest • Bristlecone pines of the California White Mountains are the oldest Pines - genus Pinus of the family Pinaceae • Most familiar of all conifers • About 90 species Vegetative Characters of Pine Pine Stems • Extensive branching • Christmas tree shape • Very woody Pine Leaves • Needles produced in clusters (fascicles) of 1 to 5 Pine – Reproductive Structures Pines produce pollen and seeds in cones Pines are Monecious Individual plants produce both pollen cones and seed cones Seed Cone C Pines are Monecious Individual plants produce both pollen cones and seed cones Pollen Cone C Pollen cones produce pollen C Pine Pollen • Wind pollination is facilitated by pollen morphology. Ovulate or Seed Cones Produce Seeds Young seed cone Cone scale C Mature seed cone Conifer Seed reminder Conifer Cones Yew (aril) Pine Giant Sequoia Juniper Bald Cypress Conifer Leaves Map of Living and Fossil Members of Taxodiaceae (Redwood Family) Dawn Redwood Metasequoia glyptostroboides and Coastal Redwood Sequoia sempervirens Cycadophyta the Cycads Cycads Appeared on Earth 250 MYA • Greatest abundance and diversity during the Jurassic • Declined sharply during the Cretaceous radiation of the angiosperms. Cycad seeds are toxic to humans • • • • Cyanobacteria in roots of cycads Flying foxes eat neurotoxic cycad seeds Humans eat the flying foxes Humans get sick (neurological disorders) Cycads Australian Mexican African Only Cycad Native to the US In Florida Zamia integrifolia Host Plant for Atala Butterfly Cycads contain cycasin, a toxic secondary plant chemical. Cycads are toxic to humans, dogs and livestock. Cycasin is found in the atala butterfly and other organisms find it distasteful and avoid eating it. Gymnosperms Cycads Conifers Ginkgos Bryophytes Pteridophytes